Final answer:
An informal credit arrangement with a customer for payment after a sale is an account receivable, representing money owed to a company for goods or services delivered on credit.
Step-by-step explanation:
An informal credit arrangement with a customer for payment to be received after the sale is classified as a account receivable. This term refers to the money owed to a company by its customers for goods or services that have been delivered but not yet paid for. Essentially, it is a line of credit that the company extends to its customers, allowing them to pay for the products or services at a later date. This concept is different from a note payable, which is a written promise to pay a debt. An account receivable is recorded on the company's balance sheet as a current asset, as it represents money that is expected to be received within a short period, typically within one year or less.